Low-Key Birthday Dinner in Manhattan

I'm looking for a good, relatively inexpensive restaurant to hold a low-key birthday dinner for around 10-15 people. Is there anywhere that's not too cramped, where it wouldn't be a problem for people to come and go (i.e. the waitress won't freak out if people come late or more people show up than RSVP'ed)?

I'm relatively new to Manhattan (and even newer to Chowhound...first post!) so any suggestion would be a great help! Thanks!

Neighborhood? Cuisine? Price range (cost per person with/out drinks tax and or tip)? I think you'd have a better chance of not having the place give you a hard time if you went during the week or went to a place that's not so incredibly popular.

The two places that I can think of are Moustache, in the back garden in the East Village location (my favorite hummous anywhere, and great, fresh, brightly flavored Middle Eastern food) and Grand Sichuan, at the St Marks location. Though they may not be thrilled if people come late, they have space enough to accommodate groups, and can deal with some of the stuff you described.

egit -- Any neighborhood, any cuisine. :) Yup, I think I'm looking for something a little more off-the-beaten-path to make sure we can fit/take our time/etc. I don't know how realistic this is, but I'm looking at $10-15/person budget is w/o drinks & tips.

rose water -- thanks for the suggestions! will definitely check them out

That's a pretty small budget, and given you want a relaxed atmosphere where people can come and go comfortably, how about a lounge or bar with food where you can reserve a banquet or table?For something super low key and fun you can go to Valhalla (54th and 9th), a bar with a fabulous international beer selection, grab one of their picnic style tables and order into the bar from any of the restaurants in the neighborhood (they don't have a kitchen, so people do this all the time), it'll be cheap and people can get whatever they want.

I had a birthday dinner at Jeeb in the LES for about 12-14 people. I know they have a nice garden in the back as well. The food was good and fun to share (the bill was really inexpensive - it helped that it was byo at the time, it now charges a corking fee). It's thai but they have lots of thai tapas which we ordered for the table.The staff was really nice, even when we made them open MANY bottles of wine.